Generally, a wireless access node system such as a base station includes a base station main body part for transmission and reception signal processes and a plurality of radiation elements, and has been classified with an antenna transmitting and receiving a wireless signal. The base station part is installed at a low position on the ground, the antenna part is installed at a high position such as a roof of a building or a tower, and the base station part may be connected to the antenna part through a feed cable.
Recently, on the strength of the increasing ease of tower installation according to the shrinking and lightening of devices for processing wireless signals, a structure in which a Remote Radio Head (RRH) processing a transmission and reception wireless signal is installed at the front end of an antenna has widely been applied so as to compensate for a cable loss when a signal is transmitted between the antenna and the base station main body part.
That is, the base station main body part for processing the transmission and reception signal is divided into an RF signal processing part and a baseband signal processing part, only the baseband signal processing part is included in the base station main body part, and the RF signal processing part is included in the remote radio head. In this event, the base station main body part may be considered as a “baseband signal processing equipment”. In this event, generally, the base station main body part (baseband signal processing equipment) is connected to the remote radio head through an optical cable transferring the transmission and reception signal in an optical communication scheme in order to prevent a mutual transmission signal loss, and a coaxial cable which is a power supply cable for supplying an operation power source of the remote radio equipment.
FIG. 1 illustrates an example of a schematic whole block configuration of a base station where a remote radio head is installed. In an example of FIG. 1, a structure in which the base station divides a corresponding cell into three sectors and provides a service has been described. Referring to FIG. 1, each of first to third antennas 11, 12, and 13 is installed for each sector in a pillar of a tower, and each of first to third remote radio heads 21, 22, and 23 is installed for the each first to third antennas 11, 12, and 13. Between the first to third remote radio heads 21, 22, and 23 and a baseband signal processing equipment 1, first to third optical cables 213, 223, and 233 for transmitting a transmission and reception signal in an optical communication scheme are connected to first to third coaxial cables 214, 224, and 234 for supplying power.
As shown in FIG. 1, it is noted that in a base station of a structure having three sectors, three optical cables 213, 223, and 233 and three coaxial cables 214, 224, and 234 are installed between the baseband signal processing equipment 1 and the remote radio heads 21, 22, and 23 so that a total of six cables, which are a relatively large number, should be installed. As described above, an increase in the number of installation cables makes a cable connection task, which takes place in a high altitude task, more difficult and, especially, equipment costs and installation costs of a cable significantly increase.
FIG. 2 is a bottom view of a configuration of a first remote radio head 21 in FIG. 1. Referring to FIG. 2, the remote radio head 21 includes one or more optical cable connection terminals (sockets) 211 for connecting one or more optical cables (a connector thereof) and a coaxial cable terminal connection terminal (sockets) 212 for connecting a coaxial cable (a connector thereof). FIG. 2 illustrates an example in which four optical cable connection terminals 211 are included, and, for example, is a structure in which multiple (i.e., four) optical cables are installed to satisfy a large capacity a data transmission standard required for LTE-A service support.
As described above, the multiple optical cables may be connected to each of the remote radio heads 21, 22, and 23. In that case, it can be known that problems in cable connection tasks and equipment and installation cost of the cable increase.